Fix python interpreter path for el6

On el6, the python interpreter is not found at /bin/python, so let's
use /usr/bin/python in tests/runtestdefaultsupprs.py.in.

	* tests/runtestdefaultsupprs.py.in: Use the python interpreter at
	/usr/bin/python, not the one at /bin/python.

Signed-off-by: Dodji Seketeli <dodji@redhat.com>

tests/runtestdefaultsupprs.py.in

@@ -1,4 +1,4 @@
-#!/bin/python
+#!/usr/bin/python
 
 '''Runs tests for the default suppression specifications of libabigail.